The 3rd generation (3G) UMTS mobile system has been widely used because of its advances in telecommunication technology. Due to its high-speed transmission capability, numerous high speed and high quality services are (and will be) provided based on 3G mobile system. However, the subscribers need to download and install new service programs before enjoying the numerous applications. In this paper, an efficient and secure application download architecture is proposed. By employing this architecture, the subscribers can securely download new applications and install them anytime and anywhere.