Following Heiko Oberdiek's answer, I finally get the way to change one row' height (and depth):
\documentclass{article}
\usepackage{array,xparse}
\makeatletter
\ExplSyntaxOn
% #1=height, #2=depth. They should be dimexpr.
\NewExpandableDocumentCommand \setarstrut { m m }
{ \mytab_set_array_strut:nn {#1} {#2} }
\NewExpandableDocumentCommand \restorearstrut { }
{ \mytab_restore_array_strut: }
\box_new:N \l__mytab_old_arstrut_box
\cs_new:Npn \mytab_set_array_strut:nn #1#2
{
\tex_noalign:D
{
\group_begin:
% Store the old strutbox
\box_gset_eq:NN \l__mytab_old_arstrut_box \@arstrutbox
% Change the dimension of \@arstrutbox
\hbox_set_to_wd:Nnn \l_tmpa_box { \c_zero_dim } { }
\box_set_ht:Nn \l_tmpa_box {#1}
\box_set_dp:Nn \l_tmpa_box {#2}
\hbox_gset:Nn \@arstrutbox { \box_use:N \l_tmpa_box }
\group_end:
}
}
\cs_new:Npn \mytab_restore_array_strut:
{
\tex_noalign:D
{ \box_gset_eq:NN \@arstrutbox \l__mytab_old_arstrut_box }
}
\ExplSyntaxOff
\makeatother
\begin{document}
\begin{tabular}{|c|c|c|}
\hline
a & b & c \\
\hline
\setarstrut{4pt}{1.3pt}
\tiny a & \tiny b & \tiny c \\
\restorearstrut
\hline
a & b & c \\
\hline
\end{tabular}
\end{document}
I use LaTeX3 to rewrite the code, but the main idea is the same: just to modify the box \@arstrutbox.
Result:

makecellorcellspace. please edit your question and clarify what you like to obtain. – Zarko Jan 10 '18 at 04:30