Technological　innovation　and　progress　always　follow　a　certain　direction　and　trajectory.　In　the　era　of　emerging　technologies,　people　want　to　pre-identify　the　trajectories　of　technological　development　to　help　them　work　out　strategies　and　response　measures.　In　this　paper,　theory,　models　and　empirical　analysis　was　integrated.　The　paper　conducts　the　analysis　of　emerging　technologies　to　determine　potential　for　development　and　future　direction　from　the　perspective　of　the　patent　and　analysis　of　patent　data.　First　introduces　the　definition　and　development　of　technological　trajectories.　The　application　and　limit　of　S-curve　method　when　used　in　the　research　on　technological　trajectories　has　also　been　analyzed.　Using　patent　information　to　discuss　industrial　technological　trajectories　has　been　proposed,　and　an　empirical　research　on　laptop　batteries　has　been　given.　Forecasting　the　ending　of　existing　battery　technology　and　the　beginning　of　future　technology　has　been　considered　as　key　problem,　therefore　three　problems　have　been　analyzed:　increment　of　patent　quantity,　technology　updating　speed,　stakeholders.　©　2011　IEEE.