Pass Array value in cucumber .feature file

I don't think you need the square brackets.

When I pass this array "aa,bb,cc"

You have to split your string up.

When(/I pass this array "([^"]*)"$/) do |array|
  array.split(',').each{|entry| do something }
end

Note: you may want to strip the entries in case there is whitespace around them {|entry| puts entry.strip }