On SPSS I am getting a result that shows no significant impact of the independent variable on the dependent. But when I am running the data on SmartPLS I am getting a significant impact. Please suggest the reason for this.
I am not familiar with SmartPLS. But in any case, you need to provide more information. For example:
What type of model are you estimating?
Provide SPSS syntax and SmartPLS code.
Provide a small data listing that illustrates the problem.
Are the p-values from SPSS and SmartPLS quite similar (with one < .05 and the other > .05), or are they quite different from each other?
As noted above, I am not familiar with SmartPLS. But the fact that you said PLS SEM makes me wonder if SmartPLS is using maximum likelihood estimation (MLE). If it is, and if the difference in the p-values is relatively small, that could account for it, because the REGRESSION procedure in SPSS uses ordinary least squares (OLS). If this is what is going on, it boils down to using t- and F-distributions in SPSS vs. z- and Chi-square distributions in SmartPLS.
I feel the values in SPSS or Smart PLS cannot change, as they are basically performing regression. I guess you are confused based on the values that are obtained in PLS. The values are t values. Based on these t values there is the manner in which categorization is made as to whether they are significant or not. Provide specific query I could answer it better.