Electromagnetic induction (EM38) and variance quad-tree (VQT) were both applied in the field of the coastal reclamation area in north Jiangsu Province. Apparent soil electrical conductivity (ECa) measured with EM38 was used as an ancillary variable of soil salinity, and the spatial distribution of ECa was used as priori information. The optimized sampling pattern of soil salinity was designed and validated by using VQT method, and the precision of the sampling design was evaluated. Results showed that the kriged spatial distribution map of the VQT scheme was highly similar to the kriged map of total sampling sites, while sampling quantity of the former was almost 1/2 of that of the latter. With the same sampling quantity, the kriged map of VQT scheme was more similar to the kriged map of total sites than that of grid sampling scheme. With the same mapping accuracy, the sampling quantity of the VQT scheme was less than that of grid sampling scheme. Under the condition of permitted maximum difference index of 10%, the sampling efficiency of VQT method could be improved by 17.3%.The advantage of the VQT method was that the scheme sampled sparsely or intensively in terms of variability in local parts of the study area. The associated application of EM38 and VQT method provided efficient tools and theoretical basis for saving cost and improving efficiency in coastal saline region. 