To better understand the expression patterns of DWF4, expression plasmids with 35S CaMV constitutive promoter containing DWF4 gene with or without its own introns were constructed and transformed respectively into the psc1 mutant deficient in the biosynthesis of brassinosteroids (BRs). Phenotypic analysis showed that the transgenic lines TgD4 with the introns of DWF4 gene could rescue the defect of BR biosynthesis in psc1 totally, whereas the transgenic lines TcD4 without the introns of DWF4 gene could only rescue the defect of BR biosynthesis partially. RTPCR demonstrated that the expression of DWF4 in the transgenic lines TgD4 was obviously increased indicating the expression of DWF4 gene could be enhanced by its own introns.