Normally, the multimedia content provider and network service providers are separated in mobile TV systems. The TV programs are broadcasted from the content provider to the mobile terminals through Digital Video Broadcasting Transmission System for Handheld Terminals (DVB-H), and the access information is unicasted from the service provider to the user via General Packet Radio Services (GPRS) networks. Due to the network architecture heterogeneity, protocols variation and algorithms difference, securing mobile TV content is becoming a significant challenge. In this paper, we present the architecture, protocol, user identification and digital right management (DRM) for protecting mobile TV multimedia content. The network architecture describes the integrated DVB-H and GPRS to provide secure mobile TV services. The efficient protocols and algorithms are proposed to encrypt the content and also decrypt the coded content. The user identification is able to identify the legal user by matching the username-password pair or the scanned fingerprint. The DRM is able to protect the data from both DVB-H and GPRS. Following this framework, the illegal usage of the mobile TV services can be efficiently prevented and the real-time multimedia Quality-of-Service (QoS) with respect to delay can be guaranteed. The real implementation has demonstrated the effectiveness of the multimedia content protection in the heterogeneous mobile networks. In addition, the delay is sufficiently low to provide live TV.