I solved my problem.
First of all, as Chris said. It's NOT necessary to add lib in .pro file. (LIBS += -L/usr/local/Cellar/openssl/1.0.2d_1/lib/ -lcrypto -lssl)

My problem was:
I followed this page to update my openssl (http://javigon.com/2014/04/09/update-openssl-in-osx/). However, this tutorial miss one important thing.
That is
Qt Code: 
  1. @ brew link --force openssl.
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I guess this command is important to generate needed link in the system.

For anyone who wants to solve this problem. You could also refer to http://apple.stackexchange.com/quest...penssl-in-os-x