A new 2(3→20) abeotaxane, taxumairone A (1), and a new cis-p-coumaroyl myo-inositol have been isolated from the seeds of Taxus mairei in addition to taxin B (2), taxinine A, taxuspine X, decinnamoyltaxinine E, 5α-cinnamoyloxy-9α, 10β, 13α-triacetoxy-taxa-4(20)11-diene and 5α-cinnamoyloxy-2α, 9α, 10β, 13α-tetraacetoxy-taxa-4(20)11-diene. The structure of 1 was determined by 2D-NMR spectral analysis and chemical correlation with taxin B (2). Compound 1 exhibited potent cytotoxicity against human colon carcinoma cells with an ED50 of 0.1 μg/ml.