The purposes of this research is to increase students science process skills and achievement of class VIII-B SMP Negeri 26  Surakarta through the implementation of Guided Inquiry I earning strategy.
This research is a Classroom Action Research with 4 cycles of action.  Each cycle consisting of 4 phases which is planning, acting, observing, and reflecting. Observational data obtained from the observation  and test.  Technical analysis of data is technical descriptive both qualitative and quantitative. Data validation is use split half method. Result of this research show that with the implementation of Guided Inquiry strategy  could  increase   students  science  process   skills  and  achievement  in Biological  learning.  It's  based  on  the  result  of observation  and  test.  Average procentage for each aspect of science process skills from the result of observation first cycle are 33,19%    (worked up  16,97%),  second cycle 43,22%   (worked up 10,03%), third cycle 48,23%  (worked up 5,01%), dan last cycle 60,38%  (worked up 12,15%).  Average score of knowledgedimension  of cognitive achievement on the first cycle 37)0%,  second cycle 42,64%,  third cycle 37,72%,  and the last  cycle 46,93%.   Score  of affective  achievement on  the  first cycle  18,52%  (worked up 2,3%),  second cycle 28,06%  (worked up 9,54%), third cycle 38,73%    (worked up 10,67%),  and the  last  cycle  45,22%   (worked  up  6,49%).   Score of psikomotor achievement  on the first cycle 38,95%  (worked up 22,71 %), second cycle 43,71 % (worked up 4,76%),  third cycle 46,39%  (worked up 2,68%),   and the last  cycle 48,9%   (worked up 2,51 %).  According to this  result,  can be concluded that the implementation of Guided Inquiry learning strategy could  increase students science process skills and achievement of class VIII-B SMP Negeri 26 Surakarta class year 2011/ 2012.