Run jupyter notebook in a conda env can't change kernel with correct $PATH

[scku208]

I install miniconda and create a env named "startup", then I install jupyter notebook and some extensions in it.
I also create some other envs for different jobs, named like "sci", "gis",..., install required packages in it.

run terminal with:

source activate startup
jupyter-notebook

everything looks great, open an ipynb file and run cell:

import os
os.environ['PATH']

give the path like
/Users/scku/miniconda3/envs/startup/bin:/Users/scku/miniconda3/bin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/Library/TeX/texbin:/opt/X11/bin"

run:

import sys
sys.path

give the path
['',
'/Users/scku/miniconda3/envs/startup/lib/python36.zip',
'/Users/scku/miniconda3/envs/startup/lib/python3.6',
'/Users/scku/miniconda3/envs/startup/lib/python3.6/lib-dynload',
'/Users/scku/miniconda3/envs/startup/lib/python3.6/site-packages',
'/Users/scku/miniconda3/envs/startup/lib/python3.6/site-packages/IPython/extensions',
'/Users/scku/.ipython']

but when I change kernel by "Kernel" -> "Change kernel" -> "conda env:sci"
run

import os
os.environ['PATH']

get the confusion path (still "starup", no "sci")
'/Users/scku/miniconda3/envs/startup/bin:/Users/scku/miniconda3/bin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/Library/TeX/texbin:/opt/X11/bin'

run

import sys
sys.path

get the path I expect
['',
'/Users/scku/miniconda3/envs/sci/lib/python36.zip',
'/Users/scku/miniconda3/envs/sci/lib/python3.6',
'/Users/scku/miniconda3/envs/sci/lib/python3.6/lib-dynload',
'/Users/scku/miniconda3/envs/sci/lib/python3.6/site-packages',
'/Users/scku/miniconda3/envs/sci/lib/python3.6/site-packages/IPython/extensions',
'/Users/scku/.ipython']

shouldn't the "changing kernel behavior" like (run with terminal):

#default path
KuShangChende-MacBook-Air:~ scku$ echo $PATH
/Users/scku/miniconda3/bin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/Library/TeX/texbin:/opt/X11/bin
#startup path + default path
KuShangChende-MacBook-Air:~ scku$ source activate startup
(startup) KuShangChende-MacBook-Air:~ scku$ echo $PATH
/Users/scku/miniconda3/envs/startup/bin:/Users/scku/miniconda3/bin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/Library/TeX/texbin:/opt/X11/bin
# sci path + startup path + default path
(startup) KuShangChende-MacBook-Air:~ scku$ source activate sci
(sci) KuShangChende-MacBook-Air:~ scku$ echo $PATH
/Users/scku/miniconda3/envs/sci/bin:/Users/scku/miniconda3/envs/startup/bin:/Users/scku/miniconda3/bin:/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin:/Library/TeX/texbin:/opt/X11/bin

Or I missed something? thanks for help.