The rapidity (pseudorapidity) distribution of produced particles in high-energy nucleus--nucleus collisions are studied by the thermalized cylinder model. In the calculation, two rapidity (pseudorapidity) distribution formulas for an isotropic thermal source are used. The calculated results are compared with the experimental data of Au--Au collisions at 11.5A and 10.8A GeV/c and Pb--Pb collisions at 158A GeV/c. The formula for rapidity (pseudorapidity) agrees well with data on rapidity (pseudorapidity) distribution, whereas approximating rapidity (pseudorapidity) by pseudorapidity (rapidity) leads to discrepancies in the fragmentation regions. The fit parameter \Delta y representing the rapidity interval over which isotropic sources are distributed seems to be independent on the kinds of concerned produced particles and the centrality cut in the fitted data.

PACS numbers: 25.75.--q, 24.01.Pa