In order to reduce the carbon emissions of cold chain logistics and promote the construction of ecological civilization, a logistics distribution path optimization model with the minimum total cost as the objective function under the carbon tax system was proposed. The model comprehensively considers the technical advantages of the Internet of things and the characteristics of cold chain logistics; introduces soft time window, customer satisfaction, and carbon emissions as the main constraint conditions; uses the improved genetic algorithm to solve the mathematical model; uses Matlab to encode; and shows the effectiveness and rationality of the model and algorithm through examples. The experimental results show that: The total cost is 9917.12 yuan, customer satisfaction is 97.07%, carbon emission is 161.06 kg, carbon tax is 5.64 yuan/ton, fixed cost is 600 yuan, transportation cost is 72.72 yuan, refrigeration cost is 8811.73 yuan, cargo damage cost is 427.03 yuan, penalty cost is 0 yuan, The validity of the algorithm and the rationality of the model are verified. When enterprises add a carbon tax constraint, the total cost of cold chain distribution is reduced, and the carbon emission is reduced compared with that without carbon tax. The research can provide a reference for enterprise cold chain logistics distribution decisions.