Aerosol is a key element in many research fields

such as climate changes

environment study

pollution monitoring and ground object recognition all over the world.Now the space-borne sensors have widely applied to monitor the aerosol optical properties.But there are several problems within the inversion of aerosol properties.One is the aerosol model which changes with place and season.The aerosol model can be studied through a large size of ground based meas- urement.This is the motive of establishment of AERONET（Aerosol Robotic Network）

which aims to study the world wide aerosol model using solar spectrophotometer.In Beijing

there are two AERONET observation stations

one is located in the north

the another is in the south.The north one is near the Beijing Olympic Game’s site

where were lots of pro- jects constructions from 2005.The AERONET ground measurements can be used to study the local aerosol model.Dubo- vik and King had developed a method to derive aerosol optical thickness

single scattering albedo

Angstrom exponent and polarized phase function based on four band measurements.This method is used to produce the aerosol products in AERO- NET.We used a new algorithm put forward by Li Zheng-qiang based on a polarized band measurement besides the four bands to derive more aerosol properties.The properties aerosol includes the optical properties

such as aerosol optical thickness

single scattering albedo

Angstrom exponent and polarized phase function.It also includes the physical proper- ties

such as particle size and refraction index.Based on the north AERONET observation in Beijing near Beijing Olympic Game’s site in 2005 and 2006

we compared the results from the two different retrieval algorithms.The optical and physi- cal aerosol properties had been retrieved based on ground measurements of 2005 and 2006.Then the optical and physical aerosol properties had been used to analyse the aerosol property annuel change because of the Olympic Game’s architecture projects around Beijing site.The results show that（Ⅰ）the aerosol optical thickness is getting high

and the Angstrom exponent is getting low from 2005 to 2006.It means that the project construction brought more dust.（Ⅱ）The average single scattering albedo in 2006 retrieved from the measurements is round 0.85

it is about 0.05 lower than the average value in 2005.The lower single scattering albedo indicates the stronger absorbability of aerosol particle in 2006.（Ⅲ）We also got the polarized phase function from polarized band measurements

and it changes with the Angstrom exponent. （Ⅳ）The tow-year measurements both reveal the aerosol particle size in north city of Beijing is bimodal lognormal distribu- tion.The peak values of two bimodal lognormal distribution in 2006 are higher than those in 2005.It means more granules and large particles in 2006 in north Beijing had been produced by the construction.