diff --git a/py_bind/pyproject.toml b/py_bind/pyproject.toml
index 9e51ca3..9378878 100644
--- a/py_bind/pyproject.toml
+++ b/py_bind/pyproject.toml
@@ -9,7 +9,7 @@ requires = [
 ]
 
 [tool.cibuildwheel]
-before-build = "pip install numpy cython && cd py_bind && python setup.py prepare"
+before-build = "pip install numpy cython==0.29.36 && cd py_bind && python setup.py prepare"
 test-requires = ["nose","six"]
 test-command = "cd {project}/py_bind/test && nosetests"
 skip = ["cp311-*","pp*"]