The invention discloses test paper for detecting residual thiophanate methyl in crops, and application and a preparation method of the test paper. The test paper comprises a sample absorption pad, a conjugate release pad, a reaction membrane, a water absorbing pad and a bottom plate, wherein the reaction membrane is provided with a detecting line (line T) which is coated with a thiophanate methyl coupled antigen and a quality control line (line C) which is coated with a goat-anti-mouse antibody; the conjugate release pad is coated with a thiophanate methyl monoclone-colloidal gold label. The test paper disclosed by the invention has the advantages of high sensitivity, strong specificity, low detection cost, simpleness in operation, short detection time, suitability for all units, simpleness in storage and long preservation period, is an ideal rapid screening means, is capable of well meeting the requirement on on-site rapid detecting and is specifically suitable for screening and on-site monitoring of a large number of samples.