As it has been stepping into the e-time period, software, which is considered as the key factor of the network and computer development, has become an integral part of everyday life. Millions of people may perform transaction through internet, mobile phone, ATM, and send e-mails, handle word processing or spreadsheets for different purposes. In another word, the network and information have been related to our daily life completely. Then, by IT advancing, the awareness of software security becomes a hot and serious topic. This paper will give some comments in various aspects, such as, in the beginning of the SDLC (System Development Life Cycle), how do designers analyze the functional and non-functional requirements and choose the proper development model? And then the testing professors take which kinds of methods to test the software with white-box testing or black-box testing to discover the vulnerabilities and flaws. At the same time, the paper gives some examples to demonstrate why the security of software is pretty important and what we should do to secure that. In addition, the paper will talk something about the enterprises’ actions to build a more secure network environment.