To study the effect of PDⅠadministration on dopamine receptors (DR 1, DR 2) mRNAs expression in the lesioned striatum of the PD rat model and confirm if PDⅠ has the effect of dopamine receptor agonist. The PD rats with unilateral 6-hydroxydopamine lesioned were administrated with PDⅠ, L-dopa methyl/benserazide, L-dopa methyl /benserazide/ PDⅠ, normal saline respectively for 4 weeks and their behavioral changes were observed. Then the rats were sacrificed and RT-PCR technique was used to detect changes of dopamine receptors (DR 1, DR 2) mRNAs expression in the ipsilateral striatum 1 day after the last treatment. The results showed that treatment with PDⅠplus L-dopa resulted in a stable contralateral rotation behavior; treatment with L-dopa resulted in a progressively increased contralateral rotation behavior. Rotation behavior induced by anhydromorphine decreased with PDⅠor PDⅠplus L-dopa treatment. Treatment With L-dopa or PDⅠplus L-dopa, up-regulation of DR 1 mRNA and down-regulation of DR 2 mRNA were observed in the ipsilateral striatum which were more obvious than that treated with PDⅠor vehicle (P<0.05). It was concluded that long-term treatment with PDⅠcould alleviate the behavior of PD rats. PDⅠhad no apparent effect on the dopamine receptors (DR 1, DR 2) mRNAs expression in the ipsilateral striatum and the PDⅠ has no agonist effect on dopamine receptors. To study the effect of PDⅠadministration on dopamine receptors (DR1, DR2) mRNAs expression in the lesioned striatum of the PD rat model and confirm if PDⅠ has the effect of dopamine receptor agonist. The PD rats with unilateral 6-hydroxydopamine lesioned were administrated with PDI, L-dopa methyl / benserazide, L-dopa methyl / benserazide / PDI, normal saline respectively for 4 weeks and their behavioral changes were observed. Then the rats were sacrificed and RT-PCR technique was used to detect changes of dopamine receptors (DR1, DR2) mRNAs expression in the ipsilateral striatum 1 day after the last treatment. The results showed that treatment with PDⅠplus L-dopa resulted in a stable contralateral rotation behavior; treatment with L-dopa resulted in a progressively increased contralateral rotation behavior. Rotation behavior induced by anhydromorphine decreased with PDⅠor PDⅠplus L-dopa treatment. Treatment With L-dopa or PDⅠplus L-dopa, up-regulation of DR 1 mRNA and down-regulation of DR2 mRNA were observed in the ipsilateral striatum which were more obvious than than treated with PDⅠor vehicle (P <0.05). It was done that long-term treatment with PD Ⅰcould alleviate the behavior of PD rats . PD Ihad no apparent effect on the dopamine receptors (DR  1, DR  2) mRNAs expression in the ipsilateral striatum and the PD Ⅰ has no agonist effect on dopamine receptors.