diff --git a/.travis.yml b/.travis.yml
index 8538ac20..9d0546ed 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -87,11 +87,9 @@ matrix:
     - name: "pip install under osx"
       language: shell  # osx supports only shell
       install:
-        - alias python=python3
-        - alias pip=pip3
-        - python -m pip install --upgrade pip wheel setuptools --user python
-        - pip install https://pip.vnpy.com/colletion/ibapi-9.75.1-001-py3-none-any.whl
-        - bash ./install.sh
+        - python3 -m pip install --upgrade pip wheel setuptools --user python
+        - pip3 install https://pip.vnpy.com/colletion/ibapi-9.75.1-001-py3-none-any.whl
+        - bash ./install.sh python3 pip3
 
     - name: "sdist install under Windows"
       os: "windows"
diff --git a/install.sh b/install.sh
index 2cf2043c..12a08096 100644
--- a/install.sh
+++ b/install.sh
@@ -1,5 +1,11 @@
 #!/usr/bin/env bash
 
+python=$1
+pip=$2
+
+[[ -z $python ]] && python=python
+[[ -z $pip ]] && pip=pip
+
 # Get and build ta-lib
 pushd /tmp
 wget http://prdownloads.sourceforge.net/ta-lib/ta-lib-0.4.0-src.tar.gz
@@ -11,17 +17,17 @@ sudo make install
 popd
 
 # old versions of ta-lib imports numpy in setup.py
-pip install numpy
+$pip install numpy
 
 # Install extra packages
-pip install ta-lib
-pip install https://vnpy-pip.oss-cn-shanghai.aliyuncs.com/colletion/ibapi-9.75.1-py3-none-any.whl
+$pip install ta-lib
+$pip install https://vnpy-pip.oss-cn-shanghai.aliyuncs.com/colletion/ibapi-9.75.1-py3-none-any.whl
 
 # Install Python Modules
-pip install -r requirements.txt
+$pip install -r requirements.txt
 
 # Install local Chinese language environment
 sudo locale-gen zh_CN.GB18030
 
 # Install vn.py
-pip install .
\ No newline at end of file
+$pip install .
\ No newline at end of file