Abstarct: Increasing the rate of germination and crop growth in early season can increase crop competitiveness and reduce weed damage. In this regard, in order to investigate the effects of ultrasonic waves, seed priming and herbicide application on growth and yield of cowpea (Vigna sinensis) and weeds control, a field experiment was conducted at the Research field of Shahrood University as randomized complete block design with four replications in 2013-2014. Treatments were; 1-ultrasonic waves (ultrasound) + no weeding 2-ultrasonic waves + weeding (all season) 3-ultrasonic waves + reduced herbicide dose (trifluralin 1 l.ha-1) 4-ultrasonic waves + the recommended herbicide dose (2 l.ha-1) 5-hydro-priming + no weeding 6-hydro-priming + weeding 7-hydro-priming + reduced herbicide dose 8-hydro-priming + recommended herbicide dose 9-no weeding 10-weeding 11-recommended herbicide dose 12-reduced herbicide dose. Analysis of variance revealed significant differences among treatments on plant height, leaf area index, number of leaf, number of branches, number of secondary-lateral branches, number of nodules on main stem, height of the first pod insertion, relative water content, chlrophyll content, stem and leaf dry weight, protein percent, number of pod, pod length, 100-seed weight, grain yield, biological yield and havest index. The combined use of ultrasonic waves + weeding (all season) treatment increased grain and biological yield by 62 and 52.3 percent in comparison to control (no weeding) treatment respectively. The results indicated that no significant difference was observed in grain yield, harvest index, stem and leaf dry weight, number of leaf and pod length between the application of hydro-priming + trifluralin 1 l.ha-1 and ultrasonic waves + trifluralin 1 l.ha-1 in comparison to trifluralin 2 l.ha-1 and weeding (all season) treatments. Whereas, sowing pretreated seeds by ultrasonic waves and hydro-priming in soil containing recommended trifluralin dose decreased the investigated traits in comparison to application of pre-treatments alone and recommended herbicide dose. baxsed on the results of this experiment, pre-treatment of cowpea seeds by hydro-priming and ultrasonic waves can increase growth and quality traits and finally increase crop competitiveness of cowpea with weeds in the absence of trifluralin herbicide.