Masson pine is one of the main native plantation species in South China due to its fast and easy growing characteristics. Plantation area of the species increased dramatically and its growth was significantly impacted by climate change in past decades. The relationship between net productivity of masson pine plantation and climatic factors, especially for the plantation in its northern natural distribution boundary where masson pine growth is more sensitive to changes of climatic factors, is important to understand the response of its growth to climate change. We set six 20m×20m plots in 30 years old masson pine plantation in Jigongshan National Nature Reserve of Henan Province for doing this study. Both height and diameter at breast height (DBH) of all trees were measured and six cross increment cores at breast height of three sample trees were got in each plot. Tree ring widths of the dried and burnished cores were measured with Lintab tree ring analysis system. Annul diameters and heights of the sample trees were calculated using the annul tree ring widths. Biomass and net productivity of the old masson pine stands in the past 30 years were calculated based on the regressive equations between biomass and height and DBH in this area. After that, correlations between productivity and climate factors, including monthly and seasonal temperature, humidity, precipitation, sunshine and the Palmer Drought Severity Index (PDSI), were analyzed. The regressive equation between net productivity and climatic factors of the plantation in the area was established finally. The results indicated that biomass of the plantation increased more than three times in the past 30 years, from 59.00 t/hm² in 1980 to 254.75 t/hm² in 2009, and mean net productivity of the stand was 6.64 t · hm^-2 · a^-1. Net productivity was closely correlated with climatic factors. The effects of temperature, sunlight, precipitation and humidity on net productivity were different. There were positive correlations between productivity and precipitation in last August, mean temperature in February, precipitation in March, mean humidity in May, and mean temperature and total sunlight in October. There were negative correlations between productivity and total sunlight in May, precipitation and mean humidity in October. Productivity was correlative positively with PDSI from February to September. Seventy one percent of the changes of productivity could be interpreted by climatic factors. Generally, biomass of masson pine plantation in North Subtropical Region could accumulate as high as that in low-latitude region but net productivity in the region was much less than that in low-latitude region. Annual changes of net productivity were mainly caused by climatic factors, especially the length of growing season and soil water availability in growing season. It is implied that both biomass and mean net productivity of the plantations could increase in the future due to possible increase of temperature and precipitation in the North Subtropical Region.