The population surge and climate change have stressed regional ecological environment.The dynamic quantitative assessment of ecological environment quality can provide research support for the strategy development about regional ecological environment protection and civilization construction.The existing ecological quality assessment studies in Shaanxi Province are mostly based on the statistical data at the district and county scale

but there are generally problems such as small time span and difficulties to reveal the internal driving forces.MODIS data from 2001 to 2018 were used to calculate the remote sensing ecological index (RSEI) during the growing season in Shaanxi Province.Trend analysis

Hurst index method and partial correlation analysis were used to explore the spatio-temporal evolution of ecological quality and its response to climate and human activities in Shaanxi province from 2001 to 2018 at pixel scale.The results showed that:(1) The ecological quality of shaanxi province has been continuously improved in the past 20 years.The RSEI value increased at a rate of 0.34%/a

and the area with excellent ecological quality increased continuously.(2) The variation trend of RSEI was significant and the trend of obvious improvement is dominant.The overall spatial distribution pattern of RSEI is'high in the south and low in the north’

and the MK test (p<0.05) pixels accounted for 77.89%

66.75% of the pixels significantly improved

and mainly distributed in Yan'an City and Yulin City in northern Shaanxi Province

while significantly degraded pixels accounted for 11.08%

mainly distributed in Guanzhong Plain

Qinba Mountain and other places.Hurst index showed that the future trend of RSEI was mainly anti-persistence

46.04% of pixels would change from improvement to future degradation

and 29.33% of pixels would continue to improve.(3) RSEI was positively correlated with both air temperature and precipitation

and the influence of precipitation was greater than that of air temperature.The regions with negative correlation with human activities were concentrated in Xi'an urban agglomeration and central urban region of northern Shaanxi

and the correlations was significant (p<0.05)

among the pixels

night light index (36.83%)> Precipitation (18.38%)> Temperature (7.65%).Among all land use conversion types

RSEI increased at the highest rate (0.84%/a) in the area of returning farmland to forest or grassland

while RSEI continued to decrease (0.23%/a) in the area of converting farmland to construction

reflecting the positive and negative correlation of human activities on ecological environment quality.The results fill the gap of long-term ecological environment dynamic monitoring in Shaanxi Province

and provide the basis for ecological governance and green development of the Yellow River basin.