步骤：
1.
gem sources --remove https://rubygems.org/
2.
gem sources -a https://ruby.taobao.org/ Error fetching https://ruby.taobao.org/: SSL_connect returned=1 errno=0 state=SSLv3 read server certificate B: ce rtificate verify failed (https://rubygems-china.oss-cn-hangzhou.aliyuncs.com/spe cs.4.8.gz)
3.
gem sources -l *** CURRENT SOURCES ***
问题出处：
http://stackoverflow.com/questions/4528101/ssl-connect-returned-1-errno-0-state-sslv3-read-server-certificate-b-certificat
https://gist.github.com/fnichol/867550
I had this same issue while working on a Ruby project. I am using Windows 7 64bit. I resolved this by: Downloading the cacert.pem file from http://curl.haxx.se/ca/cacert.pem. Saved that file to C:/RubyCertificates/cacert.pem Then set my environmental variable "SSL_CERT_FILE" to "C:/RubyCertificates/cacert.pem" source: https://gist.github.com/fnichol/867550
证书地址：http://curl.haxx.se/ca/cacert.pem
按照上面这位网友的方法配置了环境变量如下图
再次执行gem sources -a https://ruby.taobao.org/
报错依旧
有谁遇到过，还是我的环境变量没有配置对呢？
现在淘宝的gem停止更新维护了，目前是ruby-china维护。
gem source --remove https://ruby.taobao.org/ --add http://gems-china.org/
gem source --add http://rubygems.org/gem source -l遇到同样问题，按照https://gist.github.com/fnichol/867550 的步骤执行后顺利通过（需要注销机子）。
不过我是添加到系统变量，不知道是不是这个原因。
要添加到系统变量，重启电脑再执行切换淘宝源的命令就可以了