how to join two tables with condition may contains regex condition or array condition

Try below

#standardSQL
CREATE TEMPORARY FUNCTION similarity(Text1 STRING, Text2 STRING)
RETURNS FLOAT64
LANGUAGE js AS """
  var _extend = function(dst) {
    var sources = Array.prototype.slice.call(arguments, 1);
    for (var i=0; i<sources.length; ++i) {
      var src = sources[i];
      for (var p in src) {
        if (src.hasOwnProperty(p)) dst[p] = src[p];
      }
    }
    return dst;
  };
  var Levenshtein = {
    get: function(str1, str2) {
      // base cases
      if (str1 === str2) return 0;
      if (str1.length === 0) return str2.length;
      if (str2.length === 0) return str1.length;
      // two rows
      var prevRow  = new Array(str2.length + 1),
          curCol, nextCol, i, j, tmp;
      // initialise previous row
      for (i=0; i<prevRow.length; ++i) {
        prevRow[i] = i;
      }
      // calculate current row distance from previous row
      for (i=0; i<str1.length; ++i) {
        nextCol = i + 1;
        for (j=0; j<str2.length; ++j) {
          curCol = nextCol;

          // substution
          nextCol = prevRow[j] + ( (str1.charAt(i) === str2.charAt(j)) ? 0 : 1 );
          // insertion
          tmp = curCol + 1;
          if (nextCol > tmp) {
            nextCol = tmp;
          }
          // deletion
          tmp = prevRow[j + 1] + 1;
          if (nextCol > tmp) {
            nextCol = tmp;
          }
          // copy current col value into previous (in preparation for next iteration)
          prevRow[j] = curCol;
        }
        // copy last col value into previous (in preparation for next iteration)
        prevRow[j] = nextCol;
      }
      return nextCol;
    }
  };

  var the_Text1;
  try {the_Text1 = decodeURI(Text1).toLowerCase();} catch (ex) {the_Text1 = Text1.toLowerCase();}
  try {the_Text2 = decodeURI(Text2).toLowerCase();} catch (ex) {the_Text2 = Text2.toLowerCase();}
  return Levenshtein.get(the_Text1, the_Text2) / the_Text1.length;
""";

SELECT *, (
  SELECT t1.Item_description
  FROM `project.dataset.tab1` t1
  ORDER BY similarity(t2.Item_description, REPLACE(t1.Item_description, '|', ', ')) 
  LIMIT 1
  ) matched_description
FROM `project.dataset.tab2` t2

If to apply to sample data from your question - result will be

Row Customer_ld Item_description                                        matched_description  
1   1001        Item Lenovo x1 Yoga, i7 14" is delivered                Lenovo x1 Yoga|i7 14"    
2   1002        Lenovo x1 Yoga, i5 13" is delivered to customer         Lenovo x1 Yoga|i5 13"    
3   1003        Lenovo Yoga, i7 14" is delivered to customer@1003       Lenovo Yoga|i7 14"   
4   1004        Item lenovo x1 yoga, i7 14" is delivered successfully   Lenovo x1 Yoga|i7 14"    
5   1005        Item Lenovo x1 Yoga, i7 14" is delivered@1005           Lenovo x1 Yoga|i7 14"    

I would use regex to tokenize the features that make each description unique.

with Tab1x as (
  select 
    Item_description,
    ifnull(regexp_extract(Item_description,r'([x][0-9])'),'none') as xspec,
    ifnull(regexp_extract(Item_description,r'([i][0-9])'), 'none') as ispec,
    ifnull(regexp_extract(Item_description,r'([0-9]{2}\")'), 'none') as size
  from Tab1
),
Tab2x as (
  select 
    Customer_id,
    Item_description,
    ifnull(regexp_extract(Item_description,r'([x][0-9])'),'none') as xspec,
    ifnull(regexp_extract(Item_description,r'([i][0-9])'), 'none') as ispec,
    ifnull(regexp_extract(Item_description,r'([0-9]{2}\")'), 'none') as size
  from Tab2
)
select 
  Tab1x.Item_description as Tab1_Item_description,
  Tab2x.Item_description as Tab2_Item_description,
  Tab2x.Customer_id
from Tab1x
left join Tab2x using(xspec,ispec,size)

Note, I didn't touch Lenovo or Yoga, but if your real data set has multiple brands/models, you will need to take care of that in a similar fashion.