This paper investigates the multi-target localization in distributed passive sensor system in terms of blockchain technology. In this distributed framework, each sensor captures and analyzes the angle measurement data of targets locally, and uploads the results onto blockchain network for coordination among nodes. Subsequently, smart contracts automatically associate data obtained from external sensors to establish an estimate of the target location. We deploy a novel position estimation smart contract using Remix on Ganache private blockchain. Meanwhile, we conduct simulations of the Electronic Support Measures (ESM) sensor and Angle of Arrival (AoA) measurement process using Matlab. Finally, Experimental simulations verify the effectiveness and feasibility of the proposed algorithm for target localization in distributed passive sensor networks leveraging blockchain technology.