Floral color,petals structure,pH value,anthocyanin,flavonoid,soluble sugar and protein contents of Rosa hybrida were studied to explain the chromogenic mechanism of floral color.The floral color in different blooming stages was measured by the Royal Horticultural Society Color Chart(R.H.S.C.C.) and a CR-10 spectrophotometer.The results demonstrated that:(1)The anthocyanins content of petals was the highest before the flowers were completely in blooming,and the same time the color was the most strong.(2)The lower pH value,the darker flower red color.(3)Flower pigment mostly concentrated on the upper epidermis,the upper epidermis distribution of conical structure and the lower epidermis is flats lead to the color of upper epidermis stronger and the brightness is less than lower epidermis.(4)a^*_F and pH value,anthocyanin and soluble sugar,a^*_B and L^*_F,L^*_B,b^*_B are positively related;L^*_F and b^*_F,L^*_B and b^*_B are negatively related.(5)Among many factors influencing of color,front(bank) petal’s color is directly controlled by anthocyanin(bank of L^*),other factors indirect influence of floral color by influencing the anthocyanin(bank of L^*).