Abstract: The edge computing node of the Internet of Things introduces blockchain technology, which effectively expands the application field and value of the blockchain of the Internet of Things, but there are still security risks in the wireless nodes of the blockchain. In order to improve the security of nodes, this article proposes a service incentive algorithm. Firstly, algorithm select multi-dimensional indicators, and calculate the indicator score of the service provider node through the initialization of the blockchain node. Secondly, algorithm automatically calculate and set a higher proportion for the indicator with a lower score, and combine it according to the proportion to obtain a new trust score. When merging old and new trust scores, the trust scores of consumer nodes participating in the evaluation are considered. Then, incentive measures are set for nodes with scores below the standard and the algorithm process is repeated to encourage each service node to improve its own score. Finally, the trust score is broadcast to the district through smart contracts. Comparing the ATA algorithm and the TC algorithm, the simulation experiment shows that under the condition that the proportion of malicious nodes is different and the number of IoT nodes is gradually increasing, the node evaluation accuracy of the service incentive algorithm is higher, and the system communication delay is lower.