A method and system for detecting a target component by using a mobile terminal, and a detection method for simultaneously screening multiple target objects. The method for detecting a target component by using a mobile terminal comprises: detecting a target component by using test strips (100) to obtain chromogenic test strips (100); arranging the test strips (100) around a same circle center at equal angles to obtain an arrangement ring of test strips (100), positioning identifiers being provided on an area outside the test strips (100) on the arrangement ring of the test strips (100); performing image acquisition on the arrangement ring of the test strips (100) by using a mobile terminal, and uploading an acquired image to a data processing center, correcting the acquired image according to the positioning identifiers; determining the positions of a personalized mark area and a result display area of each test strip (100) in the image; performing segmentation to obtain images of the personalized mark area and the result display area of each test strip (100); calculating a chromogenic result of the result display area, and obtaining a test result of the target component; and outputting the test result of the target component and displaying the test result on the mobile terminal.