International Telemetering Conference Proceedings / October 29-November 02, 1990 / Riviera Hotel and Convention Center, Las Vegas, Nevada / As the code length is increasing, the search of optimum group sync codes will be more and more difficult, even impossible. This paper gives the searching method of quasi-optimum group sync codes on the small subset of PN sequences -- CVT-TAIL SEARCHING METHOD and PREFIX-SUFFIX SEARCHING METHOD. We have searched out quasi-optimum group sync codes for their lengths N=32-63 by this method and compared them with corresponding optimum group sync codes for their lengths N=32-54. They are very approximative. The total searching time is only several seconds. This method may solves the problems among error sync probability, code length and searching time. So, it is a good and practicable searching method for long code.