Two field experiments were conducted at Zarzoura Experimental Station in Etay El-Baroud El-Behira Governorate, during 2013 and 2014 seasons, to study the effect of nitrogen fertilizer with humic acid (for maize), i. e. 120 Kg N/faddan, soil humic acid (5Kg/ fad.), foliar application humic acid (5g/litter), soil and foliar application humic acid, 60 Kg N/faddan plus soil humic acid, 60 Kg N/faddan in combination with foliar humic acid, 60 Kg N/faddan plus soil and foliar humic acid on growth, yield and chemical constituents under one intercropping system 2 : 2 row maize/soybean, as well as maize sole and soybean sole.Results indicated that: 1-Maize: growth, yield and its components had significant effect for nitrogen fertilizer with humic acid except ear position %, ear diameter and rows number/ear, sole maize, 120 Kg N/faddan and 60 Kg N/faddan with soil and foliar humic treatments had the highest values, while the lowest values were obtained with foliar humic, soil humic as well as soil and humic application in both seasons. 2-Soybean: growth and yield and its components characters did not significantly affected by nitrogen fertilizer with humic acid except shoot dry weight, number of pods/plant, seed weight/plant and seed yield/faddan, the highest values were obtained in sole soybean.3- The results verified that chemical characters of maize and soybean were significantly affected by nitrogen fertilizer with humic acid except protein% and oil% in maize as well as carbohydrates% and oil% in soybean the highest values were obtained with sole treatments followed by the combination between soil application on nitrogen and soil or foliar humic acid, while the lowest values were obtained with foliar humic, soil humic as well as soil and foliar humic acid application.  4- The data of competitive relationships indicated that all the imposed treatments showed yield advantage compared with solid planting. Maximum values LER and K were obtained when applied 120 Kg N/faddan followed by 60 Kg N/faddan plus soil and foliar humic acid application. Aggressivity, maize was dominated in 120 Kg N/faddan and 60 Kg N/faddan with soil and foliar humic acid, while soybean was dominated in foliar humic and soil and foliar humic acid application.