Addressing the suboptimal transmission performance of aperiodic Cooperative Awareness Message (CAM) in cellular vehicle-to-everything (C-V2X) system, this paper proposes a C-V2X distributed resource allocation algorithm based on the prediction of CAM generation interval. This algorithm builds upon the sensing-based semi-persistent scheduling (SB-SPS) algorithm and extends the previously proposed CAM generation interval prediction model. Specifically, the proposed algorithm integrates this prediction model, enabling each vehicle connected to the C-V2X system to predict future CAM generation interval. Subsequently, the algorithm dynamically adapts resource reservation by setting the resource reservation interval (RRI) to a predicted value of future CAM generation interval and automatically incrementing the reselection counter (RC) when the predicted interval matches the current RRI. This method effectively addresses the drawbacks of fixed RRI and random RC in typical SB-SPS algorithm, thereby improving the adaptability and efficiency of resource allocation. The experimental results show that the proposed C-V2X distributed resource allocation algorithm based on CAM generation interval prediction significantly outperforms the SB-SPS algorithm in terms of the reliability of aperiodic CAM transmission.