The impact of the increasingly rapid development of technology and the internet has not only penetrated the trading industry, but also the Indonesian financial industry. This is indicated by the presence of financial technology (fintech). Financial transactions through fintech include payments, investments, lending money, transfers, financial plans and comparisons of financial products. Digital financial services or financial technology (fintech) are implemented based on the legal umbrella. This follows the issuance of Financial Services Authority Regulation (POJK) Number 77/POJK.01/2016, concerning Information Technology-Based Lending and Borrowing Services (LPMUBTI). Indonesia faces a number of challenges during the covid-19 period, starting with changes in habits, because one of the transmissions of covid is during payment transactions, giving cash is very influential in the transmission of covid, therefore the government recommends making payments using other than cash. Therefore, this study aims to determine the effect of knowledge, security, convenience and trust on the behavior of using financial technology (Fintech) systems, especially online-based payments. by using multiple linear regression. This research was conducted in the DKI Jakarta area using a survey method. Researchers used SPSS software to test research data. The results of this study obtained that knowledge and convenience had a insignificant negative effect on the system of using Fintech and security and trust had a significant positive effect on the system of using fintech.