Hi Thanh,
As per my understanding you want to plot a box chart and linear line in the same figure.
I have written a sample code which you can refer
% Create a matrix with 10 rows and 10 columns.
Y = magic(10);
boxchart(Y);
xlabel('Column');
ylabel('Value');
% To plot a linear line in same figure
hold on
X = 1:50;
plot(X);
To further explore the functions you can refer to below links:
Hope it helps!
