The invention discloses a telecine signal detecting method, comprising the steps of: A. calculating primary absolute difference between interleaved scanning signals of the (n+2)th and nth frames and according to the primary absolute difference, obtaining a 3 : 2 converted detection sequence; simultaneously, according to two adjacent primary absolute differences, calculating secondary absolute difference and according to the secondary absolute difference, obtaining a 2 : 2 converted detection sequence; B. determining whether the obtained detection sequences accord with the respective standard detection sequences: if yes, it is a telecine signal corresponding to the standard detection sequences; otherwise it is a non-telecine signal. And the invention alos advances a telecine signal detecting device and display. And the invention can effectively improve telecine signal detection accuracy.