In proof-of-work-based blockchain networks, the block miners participate in a crypto-puzzle solving competition to win the reward of publishing (i.e., mining) new blocks. Due to the remarkable difficulty of the crypto-puzzle, individual miners tend to join mining pools to secure stable profits. We study the dynamics of mining pool selection in a blockchain network, where mining pools may choose arbitrary block mining strategies. We identify the hash rate for puzzle-solving and the block propagation delay as two major factors determining the mining competition results. We then model the strategy evolution of individual miners as an evolutionary game. We provide the theoretical analysis of evolutionary stability in the pool selection dynamics for a two-pool case. Numerical simulations support our theoretical findings as well as demonstrate the stability in the evolution of miners' strategies in a general case.