Objective To investigate the effects of different foot-strike patterns during running on Achilles tendon (AT) morphology and mechanical loading. Methods Fourteen habitual rearfoot strike runners and 14 habitual forefoot strike runners were recruited. Morphological characteristics (tendon length, cross-sectional area, and thickness) of the AT were collected using ultrasound imaging. The AT loading characteristics (plantar flexion moment, tendon force, load rate, impulse, and stress) of subjects wearing cushioned running shoes while running at a speed of 10 km/h were collected and calculated using a three-dimensional force measurement treadmill. Results Compared to habitual rearfoot strike runners, habitual forefoot strike runners showed a significant increase in peak plantar flexion moment of ankle joint, AT peak force, average loading rate, and peak loading rate (P < 0.05). However, the differences in AT length, cross-sectional area, and thickness between the two groups were not statistically significant (P>0.05). Conclusions Long-term forefoot strike patterns can adaptively enhance the mechanical loading characteristics of the AT during repetitive stretch-shortening cycles.