The invention relates to the technical field of coke raw material sampling, sample preparation, detection and analysis, and provides a belt online full-automatic coke sampling, sample preparation, analysis and determination system and method, and the system comprises a sampling transmission unit, a granularity determination unit and a robot sample preparation analysis unit; the system has intelligence, multiple sets of sample preparation process application programs are built in the system for selection, and the sample preparation, measurement and analysis processes can be automatically and flexibly set through a control center computer or a field operation control touch screen. The system has high efficiency, and 96 batches of samples can be detected and analyzed per day; the system has transparency, information of the whole sample preparation process is archived, and video monitoring of the whole process is stored and checked; the system has accuracy, and samples are prepared and analyzed, and the whole process of prefabricated cleaning samples of different batches of materials is cleaned. Compared with a traditional coke sampling and sample preparation system, the coke sampling and sample preparation system is high in accuracy of granularity measurement, mechanical strength measurement and moisture analysis data, high in sample preparation representativeness, high in automation degree and high in sample preparation efficiency.