Abstract: Purpose/Significance Given the information loss about the heterogeneous behavior preference of decision makers in the multi-attribute decision-making of investment project, an improved multi-attribute behavior decision-making method for investment project schemes is proposed based on mental accounting and prospect theory. Design/Methodology The mental accounting established with benefit-type attribute and the cost-type attribute are evaluated independently. Value functions are constructed for different accounts considering the behavioral parameters, such as the asymmetry, reference points, risk attitudes of decision-maker’s perception of gains and losses. After standardizing the mixed evaluation information of real number types, three-parameter interval numbers and linguistic fuzzy number type attributes, this paper uses the piecewise value function to calculate the prospect value of gains and losses. As a result, the calculations of the weighted comprehensive prospect value of expert evaluation are taken as a basis of preferred scheme. Findings/Conclusions The multi-attribute behavior decision-making method based on the mental accounting and prospect theory incorporates the preference information of experts on different scheme attributes into the decision-making process, thereby achieving satisfactory decision-making.