Blockchain is favored for its characteristics of decentralization, non-tampering and traceability. As a large-scale application of blockchain technology, the PoWbased(Proof Of Work) block-generating method used by Bitcoin has always been a hot topic in the field of blockchain. This paper proposes a TPS(Transaction Per Second) model that can validly describe the PoW-based block-generating method and constructs a simulation experiment. Besides, actual data does not reach the peak of TPS, we assume that each block is full of transactions and get a set of fixed data. By comparing the fixed data, it can be found that when the block size is 1MB, the average relative error between the experimental results and the fixed TPS is 13.00%. The average relative error between the calculated results and the fixed values is 16.90%. When the block size is 4 MB, it is 14.93% and 15.25% respectively. The experimental results show that the proposed model can validly describe the TPS of the blockgenerating method based on PoW when it works saturated.