BACKGROUND:: During the process of articular cartilage recovery, the cytokines commonly used in laboratory are disadvantageous due to shortened half-life and highly cost, which limit their use in clinic. OBJECTIVE:: To investigate the effect of connective tissue growth factor (CTGF) on the proliferation and phenotype of rabbit articular chondrocytes cultured in vitro, thus providing a new cytokine for articular cartilage defect recovery in tissue engineering. DESIGN, TIME AND SETTING:: The randomized block controlled experiments were performed in Shenzhen Longgang Central Hospital from August 2007 to February 2008. MATERIALS:: Two healthy one-month-old New Zealand rabbits were recruited in this study. CTGF was produced by Propetech. METHODS:: The harvested rabbit articular cartilage was sheared, and chondrocytes were isolated and cultured by using collagenase II digestion. When cells reached 80% confluence, cells were passaged by trypsinization. Cells of the second passage were cultured in vitro and randomly divided into two groups after adherence. The experimental groups were cultured in DMEM with 30, 50, 100 and 150 μg/L CTGF, while the control group was given with DMEM only. MAIN OUTCOME MEASURES:: Cell morphology and number were observed under an inverted phase contrast microscope. Methyl Thiazolyl Tetrazolium (MTT) assay method was adopted to observe the influence of CTGF with different concentrations to the proliferation of chondrocytes, and immunohistochemical method (SABC) was used to assay the expression of type II collagen. RESULTS:: ①Rabbit articular chondrocytes under CTGF grew rapidly, which showed a typical chondrocyte appearance, some of them aggregated to form cartilage nodulars. ②CTGF could significantly promote the proliferation of rabbit articular chondrocytes, which had a significant different compared with the control group (P < 0.01). Various concentrations of CTGF were effective to promote the chondrocyte proliferation and the optimal CTGF concentration was 100 μg/L (P < 0.01). ③The rabbit articular chondrocytes under CTGF had shown to keep type II collagen expression positive and increasing. CONCLUSION:: CTGF can promote the proliferation of rabbit articular chondrocytes cultured in vitro, enhance the expression of cartilage specific type II collagen and maintain its phenotype. CTGF is a potential approach to be used as a new growth factor in recovering articular cartilage defect and treating osteoarthritis.