Investigation was conducted on secondary soil salinization of 7 planting greenhouse vegetable
bases in Chifeng City，and soil sample detection analysis was carried out on 2 bases being planted for longer years.
The results showed that the contents of soluble salt in greenhouse soil was increasing first then reducing. The soil
soluble salt content in 0-5 cm soil layer after 10 years planting could reach the highest level 11.4 g·kg^-1，which
was significantly higher than the neighbouring open fields. Along with the deepening of topsoil cultivation，the soil
soluble salt content showed a tendency of decreasing，（0-5）cm ＞（5-15）cm ＞（15-25）cm. The EC value
of greenhouse soil and main saltion content also showed a trend of first increasing then decreasing along with the
increase of planting years. There were some differences in salt composition in greenhouse soil of different areas.