Supervising how to make decision and what are the influencing variables on decision making by the activists of this field are among the most important concerns of policy makers in monetary and financial markets and particularly in stock exchange. In order to select the best stock, knowledge about the way, manner and behavior of the activists in this area will have many benefits, one of which is the optimal management of the capital market by policy makers of the public sector with timely and correct behaviors; avoiding from anomalies and creating an irrational price bubble that can be mentioned as some benefits. The purpose of this study is to investigate the relationship between demographic characteristics, risk perception and investment decision. The number of selected samples for stock buyers and analysts of capital market was 384 individuals.  Furthermore, library and field methods were used in this research to gather information. In addition to expert opinions, factor analysis and its reliability were used to calculate Cronbach's alpha in order to confirm validity and reliability. In order to analyze the obtained data from the questionnaire, SPSS and smart.pls softwares were used. Finally, in order to demonstrate the validity of the research model findings, the fitting indexes of structural equation models were used by partial least squares method and the analyzes were done with SmartPLS software. It was found that there is a significant relationship between demographic factors with risk-taking and investment decision. Also, the results showed that there is a significant relationship between risk perception and investors' decision. The results showed that education has an effect on risk taking. Also, the results showed that annual income has an effect on risk-taking and job status has an effect on risk-taking. The results also showed that gender has an effect on risk taking behavious. In terms of the fact that men are more involved in financial matters, men are riskier than women in their attitudes and behavior towards investment decisions. Investors with higher income levels are more inclined to invest in stocks compared to investors with lower income levels. Determining the amount of payment is important for investors because it helps investors to make sustainable decisions with respect to determining the budget and return of the investment portfolio. Many researches have only focused on one or more demographic factors. The current research is innovative in that it can influence several factors.