The global warming conclusion is given in 4th IPCC Assessment Report. This paper analyses uncertainties of surface temperature rise in recent 100 years from data source aspect referred in IPCC report, including spatial distribution of surface temperature observation stations, temperature series length, temperature reliability, urban heat island effect etc. It is concluded that (1) the coverage of surface temperature observation station in global skin has been low in recent 100 years; (2) spatial distribution of data source in some grid boxes is uneven; (3) there are limited long time series of temperature, and there are significant differences of annual temperature record quantities in different time periods; (4) deficient successive observations in many stations lead to low reliability of mean annual temperature; (5) most temperature records are obtained from urban stations, while heat island effect is  not fully excluded in climate change research.