The invention discloses a high-reliability machine room intelligent entrance guard opening method and an opening system. The method comprises the following steps: a user logs into a mobile phone client, and a central server generates a pseudo-random code and a time stamp and sends to the mobile phone client; the user reaches an authorized station and constructs wireless data connection; an entrance guard controller is provided with a pseudo-random code generation mechanism which is the same as that of the central server and changes with the clock, the mobile phone client sends the pseudo-random code and the time stamp, and the entrance guard controller adjusts the pseudo-random code according to the time stamp and compares the pseudo-random code with the pseudo-random code of the entrance guard controller. A mobile phone acquires the pseudo-random code and the time stamp from the central server, and the entrance guard controller adjusts the pseudo-random code according to the time stamp and compares with the pseudo-random code sent by the mobile phone, and the central server does not need to communicate with the entrance guard controller, so that the cost is reduced, and the security is improved; by pseudo-random code comparison, the reliability is improved.