The invention discloses a kit for simply and conveniently detecting RNA and protein interaction and a usage method thereof. The kit contains a UTP, ATP, CTP and GTP mixture marked with biotin, T7RNA polymerase, a cell lysis solution, streptavidin magnetic beads, lotion and protein eluent. The kit utilizes RNA to catch protein producing interaction with the RNA, RNA (such as biotin) with known sequences are firstly marked, are fixed to Beads by relying on the marks and then are co-incubated with a substance containing protein, then supernatant which does not react with the RNA is removed, the protein washed from the Beads is collected, and the obtained protein can be used for mass spectrometry or western blot experiment.