Abstract: Seed mass and specific leaf area (SLA) are two representative parameters of plant reproductive traits and vegetative traits, both of which are important parts of plant life-histories. We measured the seed mass and SLA of 63 plant species from four families (Saxifragaceae, Gentianaceae, Ranunculaceae and, Caryophyllaceae) on the eastern Qinghai-Tibet Plateau and studied how altitude and habitat influenced them. 1) The relationship between seed mass and SLA was marginally significantly negative (P=0.066). 2) Seed mass was not correlated with altitude (P>0.05) in the four families as a whole and in Ranunculaceae and Gentianaceae, but was significantly negatively correlated with altitude in the other two families. The habitats had no effect on seed mass when considered alone, but had significant effects when combined with altitude. 3) SLA significantly decreased with altitude in all four families and in Ranunculaceae and Gentianaceae but not in other two families. 4) Moreover, SLA was biggest in the meadow and least in the forest. SLA significantly decreased with altitude in the meadow, but not in other habitats. The variation of the two traits showed an active response or adaptation of the plant to the harsh environment on the eastern Qinghai-Tibet Plateau.