###### Abstract  
In recent years, with the increase in Fintech innovation, mobile payment has played an important role. This research is to investigate factors affecting consumers' willingness to use mobile payment. The study found that perceived ease of use and perceived usefulness have a significant positive impact on consumer's adoption of mobile payments. In addition, from empirical research on the mediating effect of transaction security on attitudes toward using it and behavioral intention to use, the study found that transaction security has a significant mediating effect, and empirical data shows that transaction security can strengthen consumers' behavior towards using mobile payment intention, this also explained why the penetration rate of mobile payments in developed countries is lower than in developing countries. In summary, to encourage consumers to willingly use the new mobile payment tool, in addition to making the tool easy to use and useful, it is crucial that transaction security can assure consumers' willingness to use mobile payment. mobile payment; technology acceptance model; transaction security; structural equation method +
Footnote †: journal: Applied System  
sharply to 90%. This new payment method brought unprecedented payment experience to online payment users back then. From 2007 to 2009, the annual transaction volume of Alipay increased fivefold from RMB 47.6 billion to 287.1 billion, accounting for 49.8% of the online payment market. The Ant Group subsequently introduced other financial services such as the payment tools that integrated online shopping and lending. In coherence with [PERSON] et al. (2016) Jobs to be Done theory, this disruptive innovation of decentralization and borderline decentralization, simultaneously satisfies consumers' needs in functional, social, and emotional aspects [2]. The demand has turned Ant Group into a large and successful FinTech company. In recent years, with ever-improving mobile phone functionalities, combined with better mobile internet access (e.g., from 4G to 5G), it has become easier for consumers to make payments with mobile phones. The result is an increase in mobile payments on in-person payments, in-store purchases, and online payments. Many internet platforms and startups such as FinTech have entered the field of mobile payment (e.g., LINE pay, Google pay, Apple pay, etc.). Financial institutions in Taiwan have also cooperated with these mobile payment providers to promote online credit cards. For mobile payment technology to be accepted by consumers, consumer trust is a very important factor, and transaction security is key to gaining consumer trust [1; 3; 4; 5]. Until 2016, only 60% of Taiwanese taxpayers filed tax returns online, mainly due to their distrust of the online tax filing system and fear of personal information leakage. According to the \"Mobile Payment Consumer Survey\" conducted by the Industrial Intelligence Research Institute of Taiwan Information Policy Association, the primary consideration that may affect the use of mobile payment is \"security\", which accounts for 53.1%. According to Nikkei Chinese Website (14 April 2022), the cashless ratio in 2020 is close to 30%; while the Taiwan Business Times (3 February 2021) reported that the Institute of Industrial Intelligence (MIC) of the Information Policy Council released the mobile payment consumer survey in late 2020 and reported the changes in consumer usage habits during the epidemic in early 2020. Among the common transaction methods, mobile payment (60.3%) is still lower than that of physical card (76.3%) and cash (75.5%). Transaction security is surely an important factor for consumers when using mobile payments. [PERSON] et al. (2021) explored the resistance of mobile payment [6]; relevant studies found that perceived security and privacy risks are the reasons for the resistance to mobile payment [7; 8; 9; 10; 11].