To establish a rapid construction cRNA standard curves method applicable to common laboratory, PCR was carried to amplify the target gene and internal reference gene using primers containing T7 promotor and polyT sequence, PCR product was cloned as the template of T7 RNase polymerase to synthesize cRNA in vitro for establishing standard curves. The result shows that constructed cRNA curve has a wide linear range of at least six orders and correlation coefficient is 0.99.The rapid and simple method can be applicable to measurement of transcripts for any gene.