The invention discloses a high-security computer network security controller based on a cloud system. The controller comprises a housing, a sound amplifying hole is formed in the front end of the upper surface of the shell; an alarm is arranged in the shell corresponding to the sound amplification hole; the input end of the alarm is electrically connected with the output end of the central processing unit; key holes are uniformly formed in the upper surface of the shell; a key cap is mounted in the key position hole in a matched manner; a guide post is vertically and fixedly arranged in the shell below the keycap; a mounting groove is formed in the lower end of the keycap; the guide post is clamped in the mounting groove of the key cap; according to the high-security computer network security controller based on the cloud system, the external security equipment is adopted, and the electromagnetic relay is adopted to realize mechanical power-off protection of the encrypted hard disk, sothat the security is improved, the cloud system is accessed, and password verification is carried out at the cloud end.