The Internet platform encompasses an array of software components, including mobile operating systems, transportation services, and social media networks, which synergistically form the foundation of the platform ecosystem. In this study, we have created a dynamic model that explores the competition between in-house applications (IHA) and third-party applications (TPA) within the platform ecosystem, which includes a single platform and APP developer. By utilizing simulation techniques on the dynamic model, we have identified notable factors that impact the stability of the APP competition system, including: the adjustment speed of IHA, APP heterogeneity, and TPA fees. Our findings are as follows: (1) A higher adjustment speed of IHA leads to increased system instability, resulting in a chaotic state and reduced profitability for both IHA and TPA. (2) We discovered that APP competition systems with either high or low APP heterogeneity are more prone to instability. (3) In relation to TPA fees, higher fees tend to foster greater instability within the platform ecosystem, while also increasing IHA profits. (4) We incorporate the time-delayed feedback control(TDFC) method to regulate intricate phenomena. In periods of instability, the utilization of the TDFC method can significantly mitigate the instability.