1. http://bioinfogp.cnb.csic.es/tools/venny/ （推荐） 可以最多支持四组数据对比，如：

2. http://www.bioinformatics.lu/venn.php 最多支持三组数据，但可以回收绘图后的数据，如：

3. 理论上支持无限组数据比较的Python小程序（代码高亮来自http://tohtml.com/python/）：

#! /usr/bin/env python

import os
import sys

USAGE = '''
    Descript:   Venn Diagram
    Version:    V1.0
    Author:     tudyzhb(at)gmail.com
    Data:       2013.05.08

    USAGE:
        venn.py <file1 [file2 ...]> [out_dir]

        fileX       FILE    content of a list of IDs.
        out_dir     DIR     output dir.
'''
SPLIT = '-'

def make_dir(_dir):
    if os.path.exists(_dir):
        return True
    try:
        os.makedirs(_dir)
        return True
    except:
        return False

def unique(file_name, debug = False):
    org = []
    for line in open(file_name):
        key = line.rstrip().split('\t')[0]
        if key:
            org.append(key)
    res = tuple(set(org))

    if debug:
        print >> sys.stderr, "'%s': input %d, unique elements %d" % (
                file_name, # os.path.basename(file_name)
                len(org),
                len(res),
                )
    return res

def main(file_lis, out_dir = '', debug = True):
    container = [unique(file_name, debug = True) for file_name in file_lis]

    res = {}
    for i, con in enumerate(container):# destribution elements
        idx = str(i + 1)# offset 1
        for el in con:
            if el in res:
                if idx in res[el]:
                    res[el][idx] += 1
                else:
                    res[el][idx] = 1
            else:
                res[el] = {idx:1}

    res_r = {}
    for v in res:# key to value
        key = SPLIT.join(sorted(res[v]))
        if key in res_r:
            res_r[key].append(v)
        else:
            res_r[key] = [v]

    res = res_r
    key_order = sorted([x for x in res])

    if debug:
        print >> sys.stderr, "\n**PS\t%s**\n" % ', '.join(
                ["%d:'%s'" % (x + 1, y) for x, y in enumerate(file_lis)])

    for key in key_order:# unique result elements
        res[key] = tuple(set(res[key]))
        if debug:
            print >> sys.stderr, ">%s:\t%d" % (key, len(res[key]))

    if out_dir:# output elements
        if make_dir(out_dir):
            for key in key_order:
                out = os.path.join(out_dir, "%s.txt" % key)
                try:
                    open(out, 'w').write('\n'.join(res[key]) + '\n')
                    if debug:
                        print >> sys.stderr, "output:\t'%s'" % out
                except:
                    pass

if __name__ == '__main__':
    argv_len = len(sys.argv) - 1
    if argv_len:
        argv = sys.argv[1:]
        if not os.path.isfile(argv[-1]) and argv_len >= 2:
            main(argv[0:-1], argv[-1])
        else:
            main(argv)
    else:
        print USAGE