Objective To develop a novel padlock probe and rolling circle amplification(RCA) to detect 5 common cell culture contaminant Mollicute( Mycoplasma arginini, Mycoplasma fermentans, Mycoplasma hyorhinis, Mycomplasma orale, and Acholeplasma laidlawii ). Methods "Universal" primers ( SPS1, SPA2 and SPS2, SPA1) were used to amplify the Mollicute 16S-23S rRNA intergenic spacer region.Amplicon was ligate Mollicute specific padlock probe. Probe amplified and monitored using a Corbett RotorGeneTM 6000 machine. Results Five reference Mollicute strains were correctly detected by RCA method.There was no cross-reaction. RCA method can sensitive detect 10 copies templates and show strong positive signal. Sixty-two cell culture specimens were detected. Thirty-seven samples were contained single specie Mollicute and 14 samples contained two Mollicutes. Eleven samples did not contained Mollicute. RCA detection results were concordant with previously species-specific PCR. Conclusion RCA can rapid, sensitive and specific detect contamination Mollicute.