This paper presents the formulation of a probabilistic model for a class of multi-hop wireless sensor networks. The proposed model is extended from a probabilistic model of IEEE 802.15.4 networks with a star topology. Extended into a cluster-tree topology, the model for multi-hop networks is formulated by Monte Carlo method of successful reception for uniform topology. A simple numerical result is given to determine the application of our proposed model and estimate the probability of successful collection rate. The analytical model is one of the most important technologies to estimate the probability of successful collection rate in wireless sensor networks. In the precondition of the evaluated of wireless sensor networks, how to solve the probability of success of the network topology is a very important problem with a large number of sensor nodes deployed randomly. Existing probabilistic model schemes show that network topology consists of nodes and xxx distance in distribution consuming the resources heavily. This paper presents the analytical model of wireless sensor networks which are a randomized algorithms and probabilistic analysis under a Monte Carlo simulation. With an increasing probability of successful transmission and the number of child node in each cluster, the inconsistency of networks and guarantee reception rate up to a certain of 80% percentage of the total of nodes in a symmetric topology with 100 nodes can be solved. The simulation analysis and determined that the proposed scheme can increase guarantee reception rate and estimate the probability of successful collection rate and reliability network.