Based on the Nagel-Schreckenberg (NaSch) model of traffic flow, we study the effects of the orders of the evolutive rule on traffic flow. It has been found from simulation that the cellular automaton (CA) traffic model is very sensitively dependent on the orders of the evolutive rule. Changing the evolutive steps of the NaSch model will result in two modified models, called the SDNaSch model and the noise-first model, with different fundamental diagrams and jamming states. We analyze the mechanism of these two different traffic models and corresponding traffic behaviors in detail and compare the two modified model with the NaSch model. It is concluded that the order arrangement of the stochastic delay and deterministic deceleration indeed has remarkable effects on traffic flow.