In order to improve the operating simplicity of the Up-converting Phosphor Technology-based biosensor(UPT-based biosensor),a novel signal processing algorithm is improved.The UPT-based biosensor is an optical biosensor,where a kind of up-converting phosphor(UCP) particle serves as the biological marker.The original signal is preprocessed by cross-correlation technique to get a copy of backup-data.These backup-data are used to fix on the borderlines of the function lines(the test line T and the control line C) of the UPT immune chromatographic test strip.And,the borderlines of the function lines are determined automatically with the adaptive borderline orientation algorithm.The areas of the graphics consisted of the borderlines,the signal curve and the position axis for each function line are calculated,and the test line signal ST and the control line signal SC are obtained.The ratio R of ST to SC,which is proportional to the concentration of the target analyte,is used as the judgment information.A group of standard samples are tested depend on the above algorithm in a series of experiments.It is proved to have high sensitivity(~ng/mL) and high stability(CV<5%),which can meet the need of biomedical detection.