Background and objectives: Sense of security is defined as the lack of danger and confidence that can lead to comfort and tranquility with prosperity, optimism, hope, self-efficacy, and flexibility. The aim of the present study was to explain the relationship between the sense of security and psychological capital, which has been explained at the level of Giddens' critique of existential security and Luthans' psychological capital. Methodology: A quantitative approach based on descriptive and explanatory survey was taken for this study. A questionnaire was employed as a research tool. 618 individuals from citizens aged 15 to 64 years old in Khorasan Razavi province were selected as the samples of the study. The samples were selected using Cochran's formula and simple random sampling method. The alpha value of psychological capital is equal to 0. 849 and the sense of security is equal to 0. 930. SPSS software and descriptive and inferential statistical methods were used for data analysis. Findings: Descriptive results indicate that the status of the average variable of psychological capital is low and medium and the variable of sense of security is moderate. The results of the hypotheses indicate that the variable of sense of security with the dependent variable at a significance level of 0. 05 based on correlation coefficient (0. 727) with strong intensity and based on the values of correlation coefficient of independent variable of life, moral, social, economic, family and psychological dimensions have a significant relationship with the dependent variable. According to the regression model, the components of the variables the psychological, economic, moral and life sense of security explained about 79. 4% of the changes of the dependent variable. Results: Institutionalizing existential security based on the absence of risk and building trust can flourish psychological capital, and with cooperation between those in charge of security, culture, and society, hope, optimism, self-efficacy, and flexibility can be built into citizens' behaviors.