The invention relates to the field of 
wireless communication, and in particular relates to a method and device for detecting a 
system frame number of a long-term evolution (LTE) 
system. The method comprises the following steps of: equally dividing a scrambling sequence C of a TTI (
transmission time interval) into four sections by using the self-decoding characteristic of PBCH (physical broadcast channel) data of a 
wireless frame, respectively descrambling with the PBCH data generated in the first step, after matching a descrambling rate, selecting whether to adopt a 
merge algorithm or not according to a condition, and then carrying out channel decoding and CRC (
cyclic redundancy check), judging whether to continuously receive the data of a next 
wireless frame or not according to a CRC result, and determining the 
system frame number according to the adopted scrambling sequence. The device comprises a receiving module (10), a 
signal processing module (20) and an adjudicating module (30). The invention can improve the efficiency of a terminal in the blind check of the PBCH, decreases 
power consumption, and determines the system frame number as quickly as possible, so as to be convenient to the read of a subsequent system message.