Heavy metal contamination of soil due to industrial effluents and sewage sludge used for agriculture poses a serious ecological concern and its remediation is needed to eliminate risk to the environment. Though the heavy metals are essential for plant growth but at higher concentration these metals may have a deleterious effect on plant growth. phytoextraction which is an ecofriendly cleanup technology is a type of phytoremediation that exploit the ability of plants to take up metals from soils and sequester them in their shoots. For effective planning, design and application of phytoextraction program, models have emerged as a valuable tool. Literature review revealed that very few mathematical models have been developed for phytoextraction during the last decade due to the complexity of the soil–plant–atmosphere continuum. The objective of this study was to develop simple models for phytoextraction of Ni polluted soils. The models of phytoextraction were established based on soil and plant responses to Ni pollutants. In the first section, the soil adsorption isotherm and the plant uptake rate of Ni were determined and simple models to predict the time needed for remediation of soil were proposed. In the second section the relative yield, relative trairation rate and plant Ni uptake as a function of total Ni concentration in the soil were presented. To verify the mathematical models, an experimental setup was established in greenhouse to obtain the required data. Consequently, large quantity of a sandy clay loam soil was completely mixed with Ni to obtain homogenous concentration of this pollutant within the soil matrix. The contaminated soils were then packed into the pots. Basil ( Ocimum tenuiflorum L .) seeds were planted in the pots. The total concentrations of Ni in the soil and plant samples were extracted by wet oxidation method. The water- soluble fraction of soil Ni was obtained by leaching with distilled water for 24h at 1:2 soil-liquid ratios and measured with flame atomic absorption spectrometry instrument. The result showed that adsorption of Ni on soil was fitted to Freundlich and Linear isotherm model. Due to simplicity of linear model, this model was selected. The result showed that phytoextraction rate in Ni by Basil is a first-order function of Ni concentration in soil solution. With combining these two functions, a simple model was derived to predict the required time for remediation of soil Ni (R 2 =0.96). With combining plant relative yield model with plant concentrations a model was derived to predict the phytoextraction rate of Ni (R=0.9). Also Combining the relative trairation rate model with total concentration of soil Ni indicated a reasonable performance to predict the phytoextraction rate (R=0.64). The results showed that modified Prasad equation had a reasonable performance to predicte water used by plant, however with increasing concentration of Ni in soil, the