Abstract: For oil and gas reservoirs with complex types and in new fields, the determination of the key parameters for reserve evaluation has a great significance and is also the difficulty and focus of exploration and development. At present, the mainstream practice in the world is to establish reliable technologies for conducting reserve evaluation. In China, the main exploration and development technologies are focused, but there is little research on reliable technology for reserve evaluation. In recent years, domestic companies have successively made major oil and gas breakthroughs in deep formations with a depth of nearly 10000 m and deep-sea area with a water depth of more than 500 m. The reserve evaluation of ultra-deep large-scale carbonate fractured-cavity type oil and gas reservoirs and deep-sea oil and gas reservoirs discovered in the exploration and evaluation stages faces problems such as limited data, investment constraint and low degree of well control. As a result, how to select or establish reliable technology to conduct reserve evaluation has become the research focus in this field. By starting from the definition and applicability of reliable technology, and focusing on challenges such as great exploration investment, inability to deploy exploration wells in a large area, and the complexity, particularity and uncertainty in the process of reserve evaluation for deep fractured-cavity type oil and gas reservoirs and deep-sea oil and gas reservoirs, research on the applicable conditions and scope of reliable technology in selecting key reserve evaluation parameters has been conducted. The typical case study shows that reliable technology such as amplitude-offset (AVO),direct hydrocarbon indicator (DHI) and pressure system method enables to identify oil-water contact of deep-sea oil and gas reservoirs, with a success rate of 92% in four blocks, which supports to reduce the investment of exploration and evaluation and the risk of development. For the deep fractured-cavity type carbonate oil and gas reservoir, seismic sensitive attributes analysis technology has been applied to determine oil and gas bearing boundary and area, which has high reliability in reservoir prediction confirmed by venting and lost circulation during drilling,logging interpretation results and production performance, with the coincidence rate of 84% between seismic reservoir prediction and actual drilling results, resulting in closer reserve evaluation results to the actual oil and gas reservoirs, ensuring the rationality of reserve evaluation results in the case of few wells, and promoting the application of reliable technology in the field of reserve evaluation.