Two kinds of typical artifical forests, converted from farmland in 2004, of the Ulmus pumila-Caragana microphylla and Prunus sibirica, located in southern Daxinganling sub-region, were selected for model, other two kinds of typical artificial forests, converted from farmland in 2002, of the Ulmus pumila-Caragana microphylla and Caragana microphylla, located at Otindag Sandy Land sub-region were also selected to investigate the effects of the converting engineering on the vegetation. Both the regions are part of Beijing-Tianjin sandstorm-control area. The vegetation coverage, biomass and species diversity had been monitored for four consecutive years. The results indicated that: In southern Daxinganling sub-region, the total vegetation coverage and total biomass of the Ulmus pumila-Caragana microphylla, after converted from farmland for four to seven years, were significantly higher than that of the Artemisia grassland, and the former showed an increasing trend by year but the later a wave-like trend with no significant difference within the four years. The artificial Prunus armeniaca coverage was lower than the natural lespedeza Shrub in the topphase, but it was superior to the control in later. The total biomass of Caragana microphylla artificial forests increased year by year and significantly greater than that of Lespedeza bicolor scrublands in 2010 and 2011. The total vegetation coverage of Caragana microphylla artificial forests was very significantly higher than that of Lespedeza bicolor in 2008, and the vegetation coverage of Lespedeza bicolor shrubland reduced significantly in the year of 2009 and 2010. The Shannon-Wiener index of the Ulmus pumila-Caragana microphylla, Prunus armeniaca and its counterpart plots showed a trend of wave-like change, and no obvious difference was found between them. In Otindag Sandy Land sub-region, after converted from farmland for six to nine years, the total vegetation coverage of the Ulmus pumila-Caragana microphylla was higher than that of the Caragana microphylla and open sandy land with sparse Ulmus pumila, and the Ulmus pumila-Caragana microphylla forest had a more stable annual change. The total biomass of the open sandy land with sparse Ulmus pumila was higher than that of the artificial forests of Caragana microphylla and Ulmus pumila-Caragana microphylla during 2008-2010. The biomass of the artificial forests had a more clearer increasing trend than that of natural forest. The Shannon-Wiener index of the Caragana microphylla and Ulmus pumila forests were significantly higher than that of the Ulmus pumila-Caragana microphylla. This index showed a close relation to rainfall.