Abstract: In present study we investigated the effects of porcine pseudorabies virus (PRV) infection on proliferation and heat shock protein 27,70 and 90 expression of host cells in vitro. PK-15 cells were infected with different amounts of PRV-YY strain after the titer was determined by Reed-Muench method; cell proliferation was monitored by an iCELLigence Real-Time Labeled Cell Function Analyzer after infection; levels of viral nucleic acid and the mRNA and protein expression of HSP27, 70 and 90 in PRV-infected cells were detected using Real-time fluorescence quantitative PCR (qPCR) and Western blot assays, respectively. Results were as follows:The cell indexes were decreased when cells were infected with 80 TCID₅₀ and 100 TCID₅₀ of virus (10⁶ TCID₅₀·0.1 mL^-1) within the time of detection. Sixty hours after infection, cell indexes of all treatment groups, except the group of 10 TCID₅₀ virus infection, were significantly lower than that of the control group (P<0.01). Levels of viral nucleic acid reached a peak after cells were infected with 10 TCID₅₀virus for 60 h. The transcription of HSP70 and 90 mRNA increased significantly at 0 h after infection (P<0.01), and significantly decreased at 6 and 12 h after infection (P<0.01), respectively; and the transcription of HSP27 increased significantly at 0 (P<0.05) and 3 h after infection (P<0.01), and expression of its protein significantly decreased at 48 h post of infection (P<0.01). The change trends of the three HSP proteins were similar to those of their mRNAs after PRV infection other than partial time points. The results indicate that PRV-YY infection can inhibit the proliferation of PK-15 cells, and induce rapid stress response in PK-15 cells with increasing expression of HSP27, 70 and 90. The rapid response of the three HSPs in host cells upon PRV infection may play important roles in protecting cells from virus infection.