The 29 year old, who is chasing his third European Tour title, made a poor start at Tseleevo Golf and Polo Club but recovered well with four birdies in the last six holes for a four under par 68, which took him to 11 under for the tournament.
His lead remained intact all afternoon, only briefly threatened by Belgian's Thomas Pieters, who was disappointed to bogey the last but nevertheless satisfied with a 68 and a nine under par total.
Scotland's Peter Whiteford (71) and Englishman Gary Boyd (68) are two shots further back on seven under par.
"I got off to a slow start but I managed to bounce back well," said Horsey. "I tried to do the same as yesterday and stick to my game and not worry about much else. Dropping a couple of shots early on is always disappointing, but I knew there'd be plenty of chances to come and I just needed to stay patient and keep giving myself putts for birdie. The approach shots are the key here. The fairways are wide so you don't see guys missing too many fairways. There's a bit of water, so it's just about minimising the mistakes and not giving away too many shots when you do make a mistake.
Victorian Jack Wilson is the only Australian in the field and after a fast start on Thursday he slipped back on day two and is in 20th position heading into the weekend.
Leading Round 2 scores:
133 D Horsey (Eng) 65 68,
135 T Pieters (Bel) 67 68,
137 G Boyd (Eng) 69 68, P Whiteford (Sco) 66 71,
138 N Elvira (Esp) 69 69, M Kieffer (Ger) 67 71, G Bhullar (Ind) 67 71, S Jamieson (Sco) 66 72,
139 S Hutsby (Eng) 72 67, F Andersson Hed (Swe) 70 69, K Phelan (Irl) 69 70,
140 E Dubois (Fra) 72 68, D McGrane (Irl) 69 71, S Walker (Eng) 69 71, K Eriksson (Swe) 72 68, J Colomo (Esp) 72 68, M GrÃƒÂ¶nberg (Swe) 70 70, J Doherty (Sco) 67 73, J McLeary (Sco) 68 72,
141 C Pigem (Esp) 70 71, G Charoenkul (Tha) 73 68, S Hansen (Den) 72 69, C Del Moral (Esp) 70 71, J Wilson (Aus) 67 74, L De Jager (RSA) 67 74,
142 A Saddier (Fra) 69 73, J Hansen (Den) 69 73, C Lee (Sco) 72 70, D Drysdale (Sco) 73 69,