Abstract: Mature Myriophyllum spicatum L. were planted in ponds with different turbidities (30 NTU, 60 NTU, 90 NTU), which were made by sand particles less than 100 μm. After two months growth, measurements of chlorophyll parameters were made on leaves near stems by a pulse-amplitude fluorometer (Diving-PAM) to investigate the effects of water turbidity on the photosynthetic characteristics of Myriophyllum spicatum L. The Fv/Fm and F0 of Myriophyllum spicatum L. in three turbid ponds were not significantly affected by water turbidity. The qP and ΔFv/Fm’ of plants in pond B and C (30 and 60 NTU) were not significantly decreased when compared with control, while in pond D (90 NTU) they were apparently reduced (p<0.05). Moreover, the values of qN in all four ponds were rather low (≤ 0.1). This indicates that water turbidity can’t obviously affect the function of PSII of Myriophyllum spicatum L. and most light energy are still used to drive photosynthesis while less are dissipated as heat. The diurnal variation extents of rETR in three turbid ponds were significantly smaller than that in control, indicating that the photosynthesis of plants in turbid ponds was significantly decreased with increasing water turbidity. The diurnal variation of Fv/Fm exhibited a gentle V-shape, which indicates Myriophyllum spicatum L. could endure higher irradiance. In ponds whose turbidity were higher than 60 NTU, the recovering speed of Fv/Fm was slower than that in control, but the difference wasn’t significant, which demonstrates that water turbidity showed some impact on the anti-photoinhibition ability and recovery capacity of Myriophyllum spicatum L., but the impact was not significant. The value of rETRmax was decreased with increasing water turbidity, showing that photosynthesis capacity of the plants was apparently decreased.