MEMS, deep space and deep sea exploration tasks put forward higher requirements for long-term and portable power supply. Due to its high energy density and stable power output, isotopic battery can continuously provide energy for Lunar Rover and seabed detector in extreme environments such as high and low temperature and no sunlight. As the main type of isotope battery, radio-voltaic effect isotope battery has been widely studied because of its high theoretical energy conversion efficiency and easy miniaturization, and it has been successfully applied to cardiac pacemaker. The isotope battery made of energy converters using semiconductor with wide band gap can obtain higher energy conversion efficiency. The 5.5 eV band gap and radiation resistance of single crystal diamond make it the best choice for making energy converters for radio-voltaic effect isotope batteries. With the development of chemical vapor deposition technology, the epitaxial technology of diamond crystal has made rapid progress, which has laid a material foundation for the development of diamond semiconductor devices. The characteristics of common semiconductor materials for energy converters and radiation source materials for isotopic battery are compared in this paper, the basic principle of radio-voltaic effect is introduced, then the key parameters of radio-voltaic effect isotopic battery is analyzed, and the literatures on the research of diamond radio-voltaic effect isotopic battery are summarized. The development status and existing problems of diamond isotope battery are pointed out. By analyzing the current performance and application of hetero pn junction composed of diamond and other n-type semiconductor materials, the structural design of high-performance isotope battery based on diamond hetero pn junction is given, summarized and prospected.