The priming effect refers to that when the stimulus onset asynchrony (SOA) between the two stimuli is short (including 0 msec) an observer often reports that the primed stimulus appeared first. Several Previous studies have found repetition priming effect on temporal order perception and this priming effect was due to both enhanced visual processing of the priming stimulus causing it to be perceived as having occurred earlier and a response bias to guess as the “correct” response the more highly activated primed stimulus when the observer has no distinct perception of temporal order. To explore the influence of decisional bias on location priming effect on temporal order perception, the study was conducted using the task of temporal order judgments including two response instructions (which stimulus appearing first and last). The targets of this experiment were composed of pairs of figure stimuli: a square and a diamond. Two visual targets were presented either left or right of center of the screen at short temporal intervals or simultaneously. Prior to their onsets, a red circle as a prime appeared briefly in the same location as one of the stimuli. In one block, 18 undergraduates made temporal order judgments by responding which of two shapes appeared first (TOJ-1ST instruction) and in another block, which appeared second (TOJ-2nd instruction). The experimental results showed that there were significant main effects of instruction and priming as well as a significant interaction of these factors in 84 and 42 ms SOA, and the instruction effects did not reach significance in 0 ms SOA. In conclusion, the data of the present study provided evidence to support the hypothesis that the decisional bias had a significant influence on location priming effect on temporal perception, and the mechanism of priming effect of temporal order perception involved cognitive decisions.