The invention provides a method for synchronously receiving data of an RF identification tag chip. During a stage for receiving an instruction frame head, two counters are adopted to respectively count the length of a high level 1 and a low level 0 in instruction format according with an ISO/IEC 18000-6 Type B protocol, in addition one adder having matched digit with the counters is adopted to carry out accumulation calculation to the two counters, the accumulated result namely the synchronous count value is stored in a register block. After the frame head is received, a reference value of the sample is obtained by carrying out a division calculation to the accumulated result. The count value is obtained by respectively carrying out count to the high level and low level using the two counters during the sampling. A comparator is used to respectively compare the count value with the reference value to give a correct sampling clock edge. The method has strong adaptability to low-stability on-chip clocks. The structure for circuit realization is simple, and only two counters, one adder, one comparator, a plurality of registers and a small state machine for controlling the synchronous data flow are needed.