A positron emission tomography imaging method with application adaptability and carried out with a positron emission tomography device, comprising the following steps: I. performing an initial scan for obtaining preliminary activity information of an object under detection; II. a. extracting a location and a size of a region of interest according to the preliminary activity information of the object under detection obtained by the initial scan, b. programming a performance and a layout of detector blocks and imaging parameters according to the location and the size of the region of interest in conjunction with a characteristic of the object under detection and the imaging performance requirement, c. adjusting the detector blocks according to a result of the programming so as to obtain a new system structure, and d. performing a rapid calibration for the new system structure; III. performing a scan with the new system structure for obtaining activity information of the object under detection; and IV. analyzing the activity information of the object under detection obtained in the step III; finishing the scan in a case that a quality of the activity information obtained in the step III satisfies a requirement of the application; and in a case that the quality of the activity information obtained in the step III does not satisfy the requirement of the application, re-programming the performance and the layout of the detector blocks and the imaging parameters, adjusting the detector blocks, performing rapid calibration, and repeating the steps III to IV, wherein programming the layout of the detector blocks in the step b comprises programming the detector blocks to be in a layout of surrounding the object under detection, according to the location and the size of the region of interest, a structural characteristic and an imaging characteristic of the object under detection and the performance requirement of the imaging and based on the performance and geometrical dimensions of the detector blocks in the imaging device, wherein the detector blocks are distributed on a circular detecting ring and adjusting the detector blocks comprises changing the radius of the circular detecting ring or changing the manner that sections of the detector blocks are clustered into a single aggregation or multiple aggregations, wherein the quality of the activity information of the object under detection is analyzed in the step IV, wherein the quality is one or more of a spatial resolution, sensitivity, a signal-to-noise ratio, a contrast or a metric defined by user. I. performing an initial scan for obtaining preliminary activity information of an object under detection; II. a. extracting a location and a size of a region of interest according to the preliminary activity information of the object under detection obtained by the initial scan, b. programming a performance and a layout of detector blocks and imaging parameters according to the location and the size of the region of interest in conjunction with a characteristic of the object under detection and the imaging performance requirement, c. adjusting the detector blocks according to a result of the programming so as to obtain a new system structure, and d. performing a rapid calibration for the new system structure; III. performing a scan with the new system structure for obtaining activity information of the object under detection; and IV. analyzing the activity information of the object under detection obtained in the step III; finishing the scan in a case that a quality of the activity information obtained in the step III satisfies a requirement of the application; and in a case that the quality of the activity information obtained in the step III does not satisfy the requirement of the application, re-programming the performance and the layout of the detector blocks and the imaging parameters, adjusting the detector blocks, performing rapid calibration, and repeating the steps III to IV, wherein the detector blocks are distributed on a circular detecting ring and adjusting the detector blocks comprises changing the radius of the circular detecting ring or changing the manner that sections of the detector blocks are clustered into a single aggregation or multiple aggregations, wherein the quality of the activity information of the object under detection is analyzed in the step IV, wherein the quality is one or more of a spatial resolution, sensitivity, a signal-to-noise ratio, a contrast or a metric defined by user.